I don't know how this carries over into the current legal regime, but traditionally in Chinese law it was not felt necessary to specify all possible offenses in legislation. To a large extent, people were supposed to know what was acceptable behavior, and courts could and did punish crimes that were not explicit in the legal code. In such cases, the penalty was established by analogy to other offenses. I wouldn't be surprised if the absence of an explicit offense of trespassing is due to this philosophy: everybody knows not to do it.

It's my understanding that current trespass law in the US derives from the English Common Law, although legislation in many states, e.g., Texas, has given property owners much more rights, e.g., the use of force to evict offenders, than was and is the case in England.

Other legal cultures seem to have very different approaches to issues covered by trespass law in this country, e.g., the legal principle of "right to roam" in Scotland and northern Europe and rights of access to uncultivated land in many Asian and African countries. China may be more the norm than the exception here.